Our research is directed to the study of enzymes of glycogen metabolism and factors which influence interconversion of inactive and active enzyme forms. Peptides will be used to complement inactive enzyme forms of glycogen phosphorylase from muscle to determine which amino acids of the regulatory site are essential for the allosteric transition of this enzyme. Similar studies are proposed for liver and other phosphorylases and glycogen synthase. Specificity and structural studies are proposed for interconverting enzymes phosphorylase kinase, phosphorylase phosphatase and protein kinase. A study of the involvment of pyridoxal phosphate in the regulation of enzymic interconversion of glycogen phosphorylases is suggested.